Locked cartridge fireplace firebox

ABSTRACT

In accordance with the present invention a cartridge fireplace firebox that is simple and inexpensive to manufacture, has trapezoidally shaped top and bottom walls, a backwall and sidewalls that are lined with high gloss material such as high gloss ceramic tile, a perforated metal shelf that holds both a simulated logset and one or more alcohol fuel cartridges, and a top hinged, self closing, single panel, nearly transparent wire screen front door that can be locked.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a Continuation in Part of application Ser. No. 11/440,772 by this inventor, entitled “Cartridge Fireplace Firebox”, filed May 25, 2006

FEDERALLY SPONSORED RESEARCH

Not Applicable

SEQUENCE LISTING OR PROGRAM

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention is for a cartridge fireplace firebox that is simple and inexpensive to manufacture, has trapezoidally shaped top and bottom walls, a backwall and sidewalls that are lined with high gloss material such as high gloss ceramic tile, a perforated metal shelf that holds both a simulated logset and one or more alcohol fuel cartridges, and a top hinged, self closing, single panel, nearly transparent wire screen front door that can be locked.

2. Background of the Invention

In woodburning fireplaces the area where the fire burns, called the firebox, has historically been made out of brick or similar material. More recently, factory built fireboxes made out of sheetmetal have become popular. An example of such a sheetmetal firebox used in a woodburning fireplace is shown by Bailey and Howell in U.S. Pat. No. 4,700,687.

Many such fireboxes have wire screens or curtains. Rinker, et al, in U.S. Pat. No. 4,827,902, describes a “pair of heavy gauge metal mesh curtains” (column 7, line 37). Rinker's screens hang on a rod and are manually closed. Such screens typically allow most of the light from the fire, frequently 55% to 70%, to pass through. Typically, they cannot be locked in the closed position with a lock that employs a key.

As gas fireplaces became more numerous sheetmetal fireboxes used with gas burners have also been offered. Two examples of sheetmetal fireboxes used in a gas fireplace are shown by Valters and O'Hearn in U.S. Pat. No. 6,116,232, and Wade, in U.S. Pat. No. 5,901,701.

Similar to woodburning fireplaces, some gas fireplace assemblies have wire screens in front of the fire. Lentz, in U.S. Pat. No. 4,572,156, describes a gas fireplace assembly with manually closed screen doors. Sometimes glass is used instead of screen. Berry, in U.S. Pat. No. 4,270,514, describes a gas fireplace assembly with a pair of sliding glass doors. Simington, in U.S. Pat. No. 4,029,076, describes multiple glass doors in a bay window arrangement, and May, in U.S. Pat. No. 4,290,409, describes a pair of side hinged glass doors.

Aside from woodburning and gas fireplaces, a third type of fireplace has been sold for a number of years that burns alcohol gel. Many such fireplaces burn the alcohol gel in two or three round, pint sized, paint-can type cans. The cans are placed behind a freestanding, noncombustible ceramic log. Jensen Metal Products of Racine, Wis. sells such fireplaces.

In the Jensen type fireplace both the ceramic log and the round paint cans holding the fuel are placed inside a rectangular sheetmetal firebox. The rectangular firebox has a non-glossy finish. The log and paint cans sit inside the firebox on a solid, nonperforated, sheetmetal shelf. The firebox has a pair of pull screens on the left and right, hanging on a curtain rod, that have to be pulled together to close the screen. There is no lock on the screen.

A new alcohol system for fueling a fireplace was recently revealed by this inventor in U.S. patent application Ser. No. 11/099,937. This is a cartridge system with two components. One component is a disposable, rectangular, metal cartridge filled with alcohol gel fuel. The cartridge employs various measurements and ratios that enable it to self regulate the width, flutter height, burn time and peak heights of the fire. The other component is a noncombustible logset that may be a single ceramic casting but gives the appearance of multiple log pieces. The logset is designed to ventilate the sidewalls of the fuel cartridge, which is placed substantially inside the logset, not behind it. Fire emanates from the top of the cartridge and passes through the top opening of the logset, thereby giving the appearance of a fire that rises from the middle of a group of logs, similar to a real wood fire.

Initially, the cartridge system was used by placing it inside brick fireboxes that were part of traditional woodburning fireplaces. The cartridge system was also used by placing it inside rectangular, Jensen style, non-glossy fireboxes. In the latter case the logset and fuel cartridge are placed on the Jensen style, solid, nonperforated metal shelf inside the firebox. The solid shelf did not allow optimum ventilation of the sidewalls of the fuel cartridge, but the design of the logset compensated for this with an oversized cavity and a back vent that allowed air circulation.

Despite the fact that the cartridge system could work in both Jensen style and traditional brick fireboxes, it soon became clear that these fireboxes did not take full advantage of the unique features of the cartridge burner system. A better firebox was needed.

For example, although the cartridge system produces a fire that looks extremely realistic, its primary purpose is to create ambiance as opposed to heat. Hence, a firebox designed for the cartridge system should highlight the fire's visual effect. This can be accomplished simply by lining the backwall and/or sidewalls of the firebox with a high gloss material such as high gloss ceramic tile. This enhances the illumination created by the fire by reflecting it.

The utilitarian aspects of a firebox used with the cartridge burner system are also different from existing fireboxes. For example, the sidewalls of the cartridge require significant ventilation so that the cartridge does not overheat. This invention increases the amount of air flow around the cartridge by placing it, and the logset surrounding it, on a perforated metal shelf which permits more air movement around the cartridge's sidewalls.

Other utilitarian aspects of a firebox used with the cartridge burner system are also relevant. For example, whereas some manually adjusted pull screens only allow about 55% to 70% of the light from the fire to pass through the screen, in a cartridge system much more light may be allowed to pass through the screen. This is because the cartridge system does not produce popping sparks or embers. Therefore, larger openings between the wires can be used on the screen. In fact, a nearly transparent wire screen, such that allows about 80%-90% of the light from the fire to pass through, may be used.

In addition, the cartridge system eliminates the need for multiple screens hanging on a rod or multiple glass doors. Instead, a single, top hinged frame can be used which holds the screen. Because it is top hinged, the screen defaults to the closed position when the consumer lets go of it. Hence, gravity makes this screen self closing. The screen also has a lock so it can be locked in the closed position.

Other improvements over existing fireboxes are also accomplished by the invention disclosed here, such as lessening the cost of the firebox and making it simpler to manufacture.

For example, as explained by Wade in U.S. Pat. No. 5,901,701, many sheetmetal fireboxes can be expensive to manufacture because they frequently require layers of steel welded to each other and separated by air gaps. This “steel box in a steel box” layout is how many fireboxes contain and/or dissipate the heat generated by the fire. As Wade explains, this is required because traditional fireplaces can generate as much as 40,000 BTU's of heat.

The cartridge system, however, can produce a visually pleasing fire that only generates about 5,000 BTU's of heat. Because much less heat is produced, the cartridge system does not require a “steel box in a steel box” design. For these and other reasons a firebox that took advantage of the unique characteristics of the cartridge burner system was desirable. The present invention accomplishes this result.

Disadvantages Common to the Prior Art

The applicant is unaware of any fireplace firebox that takes advantage of the cartridge burner system described by this inventor in U.S. patent application Ser. No. 11/099,937.

As discussed by Wade in U.S. Pat. No. 5,901,701, and as illustrated by the patents cited earlier, traditional firebox designs for wood or gas fireplaces require chimneys, “steel box in a steel box” designs or components required to dissipate high levels of heat, sometimes 40,000 BTU's. This makes their construction more complicated and expensive than the present invention. In addition, none of the previously cited patents describe a firebox that has trapezoidally shaped top and bottom walls, or sidewalls and a backwall that are lined with a high gloss material such as high gloss ceramic tile. Nor do they have a perforated metal shelf that holds a simulated logset surrounding a fuel cartridge, and a self closing, nearly transparent, single panel wire screen door with a lock.

Although several non-traditional firebox type inventions have been disclosed that use multiple round cans of alcohol fuel as opposed to wood or gas, none of these inventions have the features described herein. For example, Facchina, in U.S. Pat. No. 5,794,610, discloses a fireplace that burns fuel in multiple round cans which does not include a nearly transparent, self closing, single panel, screen with a lock. Nor does Facchina's invention contain sidewalls and a backwall lined with a high gloss material such as high gloss ceramic tile, or a perforated shelf supporting a noncombustible logset and fuel cartridge sitting thereon.

Similar to Facchina, Fischer, in U.S. Pat. No. 4,838,781, also discloses a fireplace apparatus that uses multiple round cans of fuel. Fischer's invention, however, does not disclose trapezoidally shaped top and bottom walls, or sidewalls and a backwall that are lined with a high gloss material such as high gloss ceramic tile. Nor does Fischer disclose a self closing, nearly transparent, single panel screen with a lock, or a perforated shelf to support a noncombustible logset and fuel cartridge sitting thereon

Similar to Facchina and Fischer, Myers, in U.S. Pat. Nos. 4,573,905 and 4,890,600, discloses fireplace systems that also burn fuel in multiple round cans. Myers' inventions do not include a self closing, nearly transparent, single panel, locked screen, nor a perforated shelf that holds a logset as shown here, nor trapezoidally shaped top and bottom walls, nor sidewalls and a backwall that increase illumination through the use of a lining made of high gloss material. Instead, both of Myers' patents increase illumination by using supplemental electric lights.

Kasulis, et al, in U.S. Pat. No. 5,469,839, disclose a reflective mechanism for fireplaces, but it has many metal parts and requires manual adjustment, whereas the present invention may consist solely of reflective tile and requires no adjustments. Byers, in U.S. Pat. No. 5,664,556, discloses a reflector mechanism, but that mechanism also consists of numerous metal parts and must be inserted into a firebox, as opposed to being built into the firebox structure itself. Fleming, in U.S. Pat. Nos. 5,678,534; 5,816,237; 6,123,066; and 6,269,809, discloses a reflector in a gas firebox that does not provide reflective images of the flame to the left and right of the flame, but only behind it, as does Jenkins in U.S. Pat. No. 4,164,931. Poulson, in U.S. Pat. No. 7,011,424 B1, discloses a candle illuminator and not a cartridge fireplace reflector.

OBJECTS AND ADVANTAGES

The objects and advantages of the invention described herein are to provide a cartridge fireplace firebox that:

-   -   (a) is simple and inexpensive to manufacture,     -   (b) enhances the illumination provided by the fire by placing a         high gloss material, such as high gloss ceramic tile, on the         back wall and side walls of the firebox,     -   (c) allows 80%-90% or more of the illumination to be visible         through the screen in front of the firebox by employing a screen         that has a large open area, such as an 80%-90% open area.     -   (d) uses a single, top hinged, self closing screen that may be         locked closed with a lock and key.     -   (e) has a perforated metal shelf that may hold both a simulated         logset and one or more alcohol fuel cartridges,     -   (f) has a perforated metal shelf that enhances the air         circulation around the sidewalls of the fuel cartridge,

SUMMARY

In accordance with the present invention there is provided a cartridge fireplace firebox that is simple and inexpensive to manufacture, with trapezoidally shaped top and bottom walls, a backwall and sidewalls that are lined with a high gloss ceramic material such as high gloss ceramic tile, a perforated metal shelf that holds both a simulated logset and one or more alcohol fuel cartridges, and a front, top hinged, self closing, single panel, nearly transparent wire screen with a lock.

DRAWINGS Figures

FIG. 1 shows the invention with the self closing screen in a partially raised position.

FIG. 2 shows the interior components of the firebox, including the perforated metal shelf, the high gloss material, such as high gloss ceramic tiles, on the side walls and back wall, and the heat absorber at the top.

FIG. 3, which is not part of the invention and is shown for illustrative purposes only, shows a noncombustible logset and a fuel cartridge that sits therein.

FIG. 4 shows the invention with Line 4 drawn as a reference point for the cross sectional view shown in FIG. 5.

FIG. 5 is a cross sectional view of the invention with a logset and cartridge therein, and a fire coming from the cartridge.

FIG. 6 shows a representative hinge mechanism.

FIG. 7 shows a representative lock and key mechanism.

FIG. 8 shows an alternative embodiment of the invention, with a glass panel in place of the self closing screen.

REFERENCE NUMERALS

-   -   1 Invention     -   12 Bottom wall     -   14 Lower face     -   16 Lower vent     -   18 Right face     -   18A Left face     -   20 Right wall     -   22 Back wall     -   24 Top wall     -   26 Left wall     -   28 Top face     -   30 Top vent     -   32 Frame     -   34 Self closing screen     -   34A Tempered glass     -   36 Lock     -   36A Key     -   38 Perforated metal shelf     -   40 Support rods     -   42 Metal heat absorber plate     -   44 High gloss material     -   46 Fuel cartridge     -   48 Logset     -   50 Cavity     -   52 Fire     -   54 Hinge     -   56 Bar latch

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT

The presently preferred embodiment of the invention is illustrated in the figures. FIG. 1 shows the trapezoidally shaped firebox formed by light weight sheet steel, such as 18 or 20 gauge steel, comprising of a bottom wall 12, right wall 20, left wall 26, top wall 24 and back wall 22. The front of the invention also has a right face 18, left face 18A, lower face 14 and top face 28. The top face 28 has top vents 30 and the lower face 14 has lower vents 16. The front of the invention has a self closing screen 34 held in the frame 32.

The frame 32 is held in place by a top mounted hinge 54. The top mounted hinge 54 can take different forms, such as a piano hinge or a pivot hinge, as is well known to those practiced in the art of making hinges. The continuous hinge shown in FIGS. 5 and 6 connects the top of the frame 32 to the top face 28. If a pivot hinge is used it will connect the top of the left and right sides of the frame 32 to the top of the right face 18 and the top of the left face 18A.

Because the self closing screen 34 is hinged at the top it will default to the closed position. The self closing screen may also be locked in the closed position with the lock 36. As is well known to those practiced in the art of making locks, the lock 36 can take different forms, such as a lock with a latch that pivots into open and closed positions. In the example shown in FIGS. 1 and 7, the lock 36 is mounted on the bottom of frame 32 and has a pivoting bar latch 56 which can pivot to a position behind the top edge of the bottom wall 12, thereby preventing the frame 32 from being lifted open, whereupon the key 36A may be removed from the lock 36, thereby locking the screen 34 in the closed position.

FIG. 2 shows the high gloss material 44, such as high gloss ceramic tile, that lines the side walls 20 and 26, and the back wall 22. FIG. 2 also shows the perforated metal shelf 38 sitting above the bottom wall 12, and the metal heat absorber plate 42 held in place by the support rods 40. The support rods 40 may be 0.25″ diameter steel, to allow substantial air movement around the rods and over the heat absorber plate 42.

During use, the logset 48 and the fuel cartridge 46, which are not part of this invention but are shown for illustrative purposes, sit on the perforated metal shelf 38, which is positioned above the bottom wall 12. As shown in FIG. 5, the fuel cartridge 46 sits in the logset cavity 50. When the cartridge is lit a fire 52 is produced. The illumination from the fire is enhanced by the high gloss material 44, thereby increasing the amount of light that leaves the firebox 1.

The vast majority of the light of the fire passes through the self closing screen 34. The self closing screen 34 may be a “two mesh” screen, meaning it has two strands of wire per lineal inch, resulting in openings that are almost 0.5″ square. The wire used for the self closing screen 9 may be relatively light, such as 0.028″ diameter wire, or heavier wire, such as 0.047″ diameter.

The transparency level of the self closing screen 34 is much higher than that of many other fireplace screens. According to the Universal Wire Company, of Morrisville, Pa., which makes fireplace screen, such screens are commonly made out of mesh with eight openings per lineal inch, using 0.028″ diameter wire. According to the charts published by Cleveland Wire Cloth, of Cleveland, Ohio, another manufacturer of fireplace screen, a mesh made out of 0.028″ diameter wire that has nine strands of wire per lineal inch (resulting in eight openings per lineal inch) has an open area of 55.95%. Using the same wire, mesh with eight strands per inch results in 60.02% open area, and mesh with only six strands per inch has 69.6% open area.

Because the current invention is made to be used with a cartridge burner system that does not produce any sparks, and may use a 2 mesh self closing screen 34 made with 0.28″ wire, the percentage of open area on the self closing screen 34 is 89.11%, meaning over 89% of the light from the fire passes through. Even if the self closing screen 34 is made with heavier wire, such as 0.047″ diameter wire, its transparency level is still about 82%. Hence, this firebox 1 allows much more of the fire to be seen through the self closing screen 34 than many other fireboxes whose screens do not close automatically.

Ambient air used for combustion enters the firebox through the self closing screen 34 or the lower vents 16. A substantial portion of the heat produced by the fire 52 will initially be initially absorbed by the metal heat absorber plate 42. Heated air exits the firebox 1 through the self closing screen 34 and through the top vents 30.

Alternative Embodiments

As an alternative embodiment the self closing screen 9 may be replaced with tempered glass 34A, also top hinged, so that it too defaults to the closed position. 

1. An alcohol fireplace firebox comprising a top wall, a bottom wall, two side walls and a back wall, wherein said firebox has a self closing front screen pivotally mounted thereon by a top hinge for pivotal movement between raised and lowered positions in which the firebox is open and closed, respectively.
 2. An alcohol fireplace firebox according to claim 1 wherein the front screen has a lock for locking the front screen in the firebox closed position.
 3. An alcohol fireplace firebox according to claim 2 wherein the lock has a removable key.
 4. An alcohol fireplace firebox according to claim 2 wherein the screen has over 80% open area.
 5. An alcohol fireplace firebox according to claim 2 wherein the firebox has a perforated metal shelf to hold a logset and an alcohol fuel source.
 6. An alcohol fireplace firebox according to claim 4 wherein the firebox has a perforated metal shelf to hold a logset and an alcohol fuel source.
 7. An alcohol fireplace firebox comprising a top wall, bottom wall, two side walls and a back wall, wherein said firebox has a self closing front glass door pivotally mounted thereon by a top hinge for pivotal movement between raised and lowered positions in which the firebox is open and closed, respectively.
 8. An alcohol fireplace firebox according to claim 7 wherein said glass door has a lock for locking the door in the firebox closed position.
 9. An alcohol fireplace firebox according to claim 2 wherein the top and bottom walls of the firebox are trapezoidal, and the backwall and sidewalls are lined with a high gloss material such as high gloss ceramic tile.
 10. An alcohol fireplace firebox comprising a top wall, a bottom wall, two side walls and a back wall, wherein the said firebox has a front screen that has a lock for locking the front screen in a firebox closed position.
 11. An alcohol fireplace firebox according to claim 10 further comprising a lock with a removable key for locking the front screen in the firebox closed position. 